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Diagnosis of Perianal Diseases
CHAPTER 5
Diagnosis of Perianal Diseases Riyadh Mohammad Hasan
Contents 1 2 3 4 5 6
Introduction History Physical Examination Digital Rectal Examination Anoscopy/Proctoscopy Laboratory Investigations 6.1 Stool Examination 6.2 Histopathological Examination 7 Imaging Studies 7.1 Fistulography 7.2 Anorectal Endosonography (Endorectal Ultrasound) 7.3 Computed Tomography 7.4 MRI (Magnetic Resonance Imaging) 8 Manometry 9 Defecography 10 Electromyography References Further Reading
33 34 34 35 36 36 36 36 37 37 37 38 38 40 41 43 43 44
1 INTRODUCTION Anorectal disorders are common, and their prevalence in the general population is probably much higher than that seen in clinical practice and hospitals, as most patients do not seek medical attention because of embarrassment (Gopal, 2002). These disorders affect men and women of all ages. The symptoms of anorectal disorders are nonspecific, ranging from mildly irritating pruritus ani to potentially severe pain (Lacy and Weiser, 2009). The diagnosis of anorectal disorders consists of taking a careful history and performing a physical examination before the patient can be subjected to various forms of investigation.
New Concepts in the Management of Septic Perianal Conditions https://doi.org/10.1016/B978-0-12-816111-1.00005-7
© 2018 Elsevier Inc. All rights reserved.
33
34
New Concepts in the Management of Septic Perianal Conditions
2 HISTORY Diagnosis of anorectal disorders begins with a medical history. Pain, bleeding, discharges (either mucoid, purulent or fecal) or change in bowel habits are the common presenting symptoms. It is also important to enquire about other associated illnesses, medications, family history, bleeding tendency, and sexual contacts (Nelson and Cima, 2007). The most evident symptom of perianal abscess is severe pain in the anal region of a short duration, usually 2–3 days. Pain is severe, throbbing in character, and increased by sitting and walking. The differential diagnoses of rectal pain are anal fissure, thrombosed hemorrhoid, levator ani syndrome, proctalgia fugax, coccydynia, fecal impaction, neoplasm (whether rectal, pelvic, or cauda equine), idiopathic, inflammatory bowel diseases (ulcerative colitis, Crohn’s disease), solitary rectal ulcer, pruritis ani, trauma, anal sex, constipation, diarrhea, familial rectal pain, endometriosis, pelvic inflammatory disease, prostatitis, and foreign body (Schubert et al., 2009). Other patients may give a history of discharge, which is generally a presenting symptom of fistula-in-ano; the discharge may either be mucoid, purulent, or fecal, and it must be differentiated from that of pilonidal sinus, hidradenitis suppurativa, and infected ruptured sebaceous cyst. Fistula-in-ano is more common in males than females, and usually arises in their third, fourth, and fifth decades of life for unknown reasons. Patients usually have a recurrent leakage of blood and pus after either surgical or spontaneous drainage of an abscess, which is a feature strongly suggestive of the development of a fistula. In some patients, the recurrence of perianal abscess may indicate the presence of an underlying fistula behind. Other general symptoms like fever (or in advanced cases, rigors and sweating) may be present. Retention of urine may be the presenting complaint in perianal abscesses.
3 PHYSICAL EXAMINATION The patient is usually examined in left lateral position with buttocks projecting slightly beyond the edge of the table. The perianal area should be inspected for any indurated, hot, tender mass felt in the region, skin tags, excoriations, scars, or any change in color or appearance. It is fairly easy to diagnose an abscess just by looking at and touching it. Intersphincteric abscesses produce few or no external features, but they can be diagnosed by the intense pain they produce, which is usually described as deep inside, and is made worse by coughing and sneezing. In supralevator abscess, the
Diagnosis of Perianal Diseases
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patient presents with fever and deep rectal pain, and there will be minimal features on external examination. Digital examination may show a tender supralevator induration above the anorectal ring. One must pay attention to the presence of fistula, which is a tract connecting two openings, one internal (which is considered the primary opening) and the other external (which is considered the secondary opening). The internal opening is often found at the dentate line, mostly at a crypt in the midline posteriorly. The treating surgeon needs to know critically important features of fistulas in order to be able to deal with them effectively. These are the primary opening, the site(s) of the secondary opening(s), the course of the fistulous track, the presence of secondary extensions, and the presence of associated diseases. The secondary opening can usually be seen as an elevated nodule of granulation tissue near the anal margin exuding pus or serosanguinous fluid. Intersphincteric fistulas usually have an external opening very close to the anal verge. Sometimes, the tract can be felt as an indurated cord, especially in simple superficial fistulas. An external opening that exudes feces or gases is mostly connected to the rectum, not to the anal canal. Defining the internal opening is the most crucial and sometimes difficult part of diagnosis and treatment. In fact, the internal opening is the crypt where the abscess originated. It may be felt during rectal examination as an indurated area. Probing was once used to define the internal opening, but probing in the awake patient is painful and may be dangerous because it may force a false tract. Many methods are used to find this opening in case it can’t be felt on rectal examination. Goodsall’s rule is a useful method of predicting the site of this opening.
4 DIGITAL RECTAL EXAMINATION This is very important examination in anorectal diseases and should not be missed. The index finger is lubricated with xylocaine jelly for digital examination, which helps in appreciating any mass, induration, stricture, apart from assessing the resting tone and strength of squeeze pressure. A gloved, lubricated finger is placed at the anal verge and gently inserted through the anal canal into the rectum. Rectal mucosa is systemically examined for benign or malignant lesions. It is possible to feel at least 10 cm from anal verge. Assessment of the anal sphincter is also made with assessment of resting tone and voluntary contraction. In males, the prostate can be assessed whereas in females, the rectocele can be detected after pushing the vaginal wall forward. (Nelson and Cima, 2007). Digital examination is probably the
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New Concepts in the Management of Septic Perianal Conditions
best way of identifying the swelling, but pain may make this examination too difficult or even impossible. Sometimes, the patient may need examination under anesthesia to get an accurate diagnosis.
5 ANOSCOPY/PROCTOSCOPY A visual examination of the lower part of rectum and anal canal through a proctoscope must be done. Anoscopy and proctosigmoidoscopy can detect any growth in the anal canal. Anoscopy enables a satisfactory examination of anal canal and distal rectum. Endoscopy in the form of sigmoidoscopy or proctoscopy is used for detecting the primary opining of the fistula but usually an anoscope can suffice, which may show the primary opening as an enlarged papilla. For complete examination of the anorectum, proctosigmoidoscopy is the preferred method. Any suspicious area can be biopsied. The proctoscope with obturator in situ is well lubricated and introduced into the anal canal; while introducing the device, one must remember that the anal canal is directed upwards and forwards towards the umbilicus of the patient. After it has been fully introduced, the obturator is taken out, and the inside of the proctoscope is well illuminated. Hemorrhoids, internal opening of the fistulous tract, anal polyps, fissures, and ulcerations can be identified (Garg et al., 2011). If doubt still exists about the location of the primary opening, a trial of injection of hydrogen peroxide with or without methylene blue and visualization of bubbles at the internal opening either directly or through endoscopy or transrectal ultrasonography. This method is also useful in the operating theater to define the internal opening prior to probing the fistula. A sigmoidoscope has the additional benefit of ruling out the presence of inflammatory bowel disease, diverticulitis with perforation and fistulization, and more seriously, low rectal and anal canal carcinoma presenting with fistula.
6 LABORATORY INVESTIGATIONS 6.1 Stool Examination Stool Examination if infectious diarrhea or sexually transmitted disease is suspected.
6.2 Histopathological Examination Histopathological Examination is done to know the histological diagnosis of the mass or the suspicious area seen in proctosigmoidoscopy.
Diagnosis of Perianal Diseases
37
7 IMAGING STUDIES Some rare deep abscesses might require ultrasound, CT scan, or even MRI for an accurate diagnosis. Imaging studies which can help determine the diagnosis in cases of a deep nonpalpable perirectal abscess include pelvic CT scan, MRI or trans-rectal ultrasound. These studies are not necessary for cases in which the diagnosis can be made upon physical examination (Beets-Tan et al., 2001).
7.1 Fistulography Fistulography is a good diagnostic method for detecting the internal opening in a fistula-in-ano, and it is still used in spite of the introduction of newer, more informative methods. This simple and affordable procedure can be done in an outpatient clinic, but it has two weak points: the inability to define secondary extensions due to insufficient filling with contrast, and the nonvisualization of anal sphincters, which is the most important factor determining the outcome of continence (Halligan and Stoker, 2006).
7.2 Anorectal Endosonography (Endorectal Ultrasound) This was the first method to show the details of anal wall anatomy, especially the sphincters (Law and Bartram, 1989). It can be used with or without injection of hydrogen peroxide, but it has an unfortunately limited field of view, making it excellent imaging procedure for the diagnosis of intersphincteric fistulas and their relationship to the anal sphincters, but less so for primary superficial, suprasphincteric, and extrasphincteric tracks or secondary extensions (Van Outryve et al., 1991, 1994). These limitations may be overcome by the improved US transducers with three-dimensional (3D) equipment (Saranovic et al., 2007). Currently, transrectal ultrasound is reserved for complicated cases, especially recurrent fistulas and supralevator fistulas where it is important to show the fistula’s relationship to the sphincters, and there is hope that it may be more widely used in the future. Transrectal ultrasounds are an accurate means of delineating anatomy in relation to a fistula. It is easily performed and less expensive than Magnetic Resonance Imaging (MRI), but it is not appropriate for the patient with severe anal pain or an anatomical stricture. The exact choice of which modality to use depends on local expertise, cost, and the equipment available.
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New Concepts in the Management of Septic Perianal Conditions
7.3 Computed Tomography Computed tomography (CT) is a useful technique for extrasphincteric fistulas, but it has limitations. It is used with rectal and intravenous contrast material, but it has poor resolution for soft tissue, which makes it unable to analyze anal fistulous tracks (Guillaumin et al., 1986; Yousem et al., 1988). The overall sensitivity of computed tomography in identifying abscess is 77%, and it lacks sensitivity in detecting perirectal abscess, particularly in the immunocompromised patient (Caliste et al., 2011). 7.3.1 Virtual Colonoscopy This procedure is done using helical CT; contrast agents may be used orally or rectally with insufflations. The accuracy of this technique may approach that of colonoscopy.
7.4 MRI (Magnetic Resonance Imaging) Adopting endoanal coils and phased array imaging has contributed to the evolution of using MRI to evaluate anorectal disease (Buchanan et al., 2004; (Berman et al., 2007) (Fig. 1). Magnetic resonance imaging is now considered the “gold standard” for fistula imaging, but it is limited by its availability and cost and is usually reserved for difficult, recurrent cases. It is used in the detection of secondary extensions, which are one of the main causes of surgical failure. In addition, it has the ability to study the integrity of the sphincter complex and to define the relationship of the fistulous track to the anal sphincters before performing fistulotomy to be sure of preserving continence. (Spencer et al., 1998; Chapple et al., 2000). In cases of recurrence and severe inflammation, the clinical examination will have difficulty delineating the position of the abscess and/or fistulous tract making planning surgical intervention very difficult and the risk of surgical failure higher. Here, MRI may indicate the site of abscess in cases in which localization is difficult, that is, intersphincteric and supralevator abscesses (Fig. 2). MRI may show the extension of an existing abscess through both ischioanal fossae to form a horseshoe abscess (Fig. 3). MRI is also useful for showing the external and internal openings and the track, and it is especially useful in recurrent fistula and cases in which there are secondary extensions (Figs. 4 and 5). MRI is useful in monitoring therapy, especially in complicated fistulas and in Crohn’s disease fistulas, and when using fibrin glue, because sometimes the external opening is closed, but the track is still not healed.
Diagnosis of Perianal Diseases
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Spermatic cords
Sartorius m. Right femoral n. Rectus femoris m. Right superficial femoral a. Right deep femoral a. Iliopsoas m. Right superficial femoral v.
Left superficial femoral a. Left femoral n. Left deep femoral a. Left superficial femoral v. Pectineus m. Pubic symphysis Prostate Prostatic urethra
Obturator externus m. Quadratus femoris m. Ischial tuberosity Sciatic n. Ischioanal fossa
Anus Internal pudendal vessels Sciatic n. Levator ani m.
Gluteus maximus m. Anococcygeal ligament
(A)
Subcutaneous fat
Spermatic cords
Sartorius m. Right femoral n. Rectus femoris m. Right superficial femoral a. Right deep femoral a. Iliopsoas m. Right superficial femoral v.
Obturator externus m. Ischioanal fossa Quadratus femoris m. Ischial tuberosity Sciatic n.
Left superficial femoral a. Left femoral n. Left deep femoral a. Left superficial femoral v. Pectineus m. Pubic symphysis Prostate Prostatic urethra Anus Sciatic n. Levator ani m.
Gluteus maximus m. Anococcygeal ligament
(B) Fig. 1 (A,B) The normal male anatomy of the perineum at the level of the mid anal canal in the axial plane. ES ¼ external sphincter, IA ¼ ischioanal fossa, InS ¼ intersphincteric space, IS ¼ internal sphincter. (From Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 268–269 (Chapter 6).)
MRI is excellent for showing the extent of healing and the effect of infliximab or fibrin glue in the process of healing (Buchanan et al., 2003; Van Assche et al., 2003). MRI may also guide surgical treatment, not only preoperatively but also intraoperatively to identify the extensions of the fistula, preventing incomplete procedures and the possibility of recurrence, especially in complex and recurrent fistulas (Gould et al., 2002). Buchanan et al. recently studied a cohort of 108 patients with recurrent fistulas using digital examination, endoanal ultrasound, and MRI on each patient. Digital
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New Concepts in the Management of Septic Perianal Conditions
Thecal sac
Erector spinae mm.
Ilium Sacrum Gluteus maximus m. Sigmoid colon Rectosigmoid colon
Rectum Ischiorectal fossa Anus
Ischioanal fossa
Levator ani m.
(A)
Ilium
Thecal sac Sacrum
Sigmoid colon Rectosigmoid colon Rectum Ischiorectal fossa Anus
Ischioanal fossa
(B) Fig. 2 (A,B) High signal intensity fluid collection along the right posterolateral aspect of the anal canal with Simple intersphincteric fistula. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 474–475 (Chapter 5).)
examination correctly identified 61% of tracks, compared with 81% of tracks found by endoanal ultrasound, and 90% by MRI (Buchanan et al., 2004).
8 MANOMETRY Surgeons may request anal manometry to further investigate problems of incontinence in defecation. Manometry tests the strength of sphincter muscle. Some authors advocate preoperative manometry in order to choose the
Diagnosis of Perianal Diseases
Sartorius m. Rectus femoris m. Pectineus m. Iliopsoas m.
Mons pubis Clitoris Left greater saphenous v. Left superficial femoral a. Left deep femoral a. Left superficial femoral v. Left deep femoral v. Pubic symphysis
Obturator externus m.
Urethra
Obturator internus m. Internal pudendal vessels
Vagina
Ischium Ischioanal fossa Gluteus maximus m. Levator ani m.
Sartorius m. Rectus femoris m. Pectineus m. Iliopsoas m. Obturator externus m. Obturator internus m. Internal pudendal vessels Ischium Ischioanal fossa Gluteus maximus m.
41
Internal pudendal vessels Anus Ischioanal fossa Horseshoe abscess Anococcygeal ligament
Mons pubis Clitoris Left greater saphenous v. Left superficial femoral a. Left deep femoral a. Left superficial femoral v. Left deep femoral v. Pubic symphysis Urethra Vagina Internal pudendal vessels Anus Ischioanal fossa Horseshoe abscess
Fig. 3 Horseshoe abscess. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 452 (Chapter 5).)
correct therapeutic management according to the risk of incontinence (Grade B) (Holzheimer and Mannick, 2001).
9 DEFECOGRAPHY Barium defecography is performed by injecting barium contrast mixed with Metamucil or another thickening agent into the rectum and taking lateral images of the anorectum during pelvic floor contraction, before, during, and after attempted defecation (Agachan et al., 1996). The angle between the axis of the rectum and the anal canal provides an indirect measure of whether the puborectalis muscle relaxes, which is the normal response, or contracts, indicative of defecatory disorder, during simulated defecation. Extra information is obtained on structural causes of outlet dysfunction
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New Concepts in the Management of Septic Perianal Conditions
Cervix Small bowel Cardinal (transverse cervical or Mackenrodt’s) ligament Lateral vaginal fornix Rectum Ischiorectal fossa Ischioanal fossa Anus
Outer cervical stroma Inner cervical stroma Cardinal (transverse cervical or Mackenrodt’s) ligament Left ovary Endocervical glands Endocervical canal Lateral vaginal fornix Transsphincteric fistula
Fig. 4 Transsphincteric fistula is distinguished by location of the internal opening in the middle third of the anal canal. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 473 (Chapter 5).)
Fig. 5 Coronal MRI STRI image reveals a right sided extrasphincteric fistula (straight arrows) with its enteric communication in the rectum (curved arrow). (From Chapman, A.H., Guthrie, J.A., Robinson, J.A., 2003. The stomach and duodenum. In: Sutton, D. (Ed.), Text Book of Radiology and Imaging, vol. 1, seventh edition. Churchill Livingstone, pp. 654 (Chapter 19).)
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including rectal prolapse, rectocele, and enterocele. Defecography was once regarded as the gold standard for diagnosis of defecatory disorder. Consequently, defecography can identify impaired evacuation in patients with symptoms of defecatory disorder, but with normal electromyography testing (Chiarioni et al., 2014).
10 ELECTROMYOGRAPHY Electromyography (EMG) may help in the assessment of anorectal incontinence, constipation, or any other pelvic floor disorder (Nelson and Cima, 2007). Anorectal disease is common and its incidence is increasing over the last few decades among populations. Diseases of the ano-rectum are usually easy to diagnose via patient’s history, which provides a great deal of information, and clinical examination with digital examination supplemented with anoscopy or proctoscopy help in diagnosis. Specialized investigations are needed in selected group of patients (Garg et al., 2011).
REFERENCES Agachan, F., Pfeifer, J., Wexner, S.D., 1996. Defecography and proctography. Results of 744 patients. Dis. Colon Rectum 39, 899–905. Beets-Tan, R.G., Beets, G.L., van der Hoop, A.G., Kessels, A.G., Vliegen, R.F., Baeten, C.G., van Engelshoven, J.M., 2001. Preoperative MR imaging of anal fistulas: does it really help the surgeon? Radiology 218, 75–84. Berman, L., Israel, G.M., McCarthy, S.M., Weinreb, J.C., Longo, W.E., 2007. Utility of magnetic resonance imaging in anorectal disease. World J. Gastroenterol. 13, 3153–3158. Buchanan, G.N., Bartram, C.I., Phillips, R.K., et al., 2003. Efficacy of fibrin sealant in the management of complex anal fistula: a prospective trial. Dis. Colon Rectum 46, 1167–1174. Buchanan, G.N., Halligan, S., Bartram, C.I., Williams, A.B., Tarroni, D., Cohen, C.R., 2004. Clinical examination, endosonography, and MR imaging in preoperative assessment of fistula in ano: comparison with outcome-based reference standard. Radiology 233, 674–681. Caliste, X., Nazir, S., Goode, T., et al., 2011. Sensitivity of computed tomography in detection of perirectal abscess. Am. Surg. 77, 166–168. Chapple, K.S., Spencer, J.A., Windsor, A.C., Wilson, D., Ward, J., Ambrose, N.S., 2000. Prognostic value of magnetic resonance imaging in the management of fistula-in-ano. Dis. Colon Rectum 43, 511–516. Chiarioni, G., Kim, S.M., Vantini, I., et al., 2014. Validation of the balloon evacuation test: reproducibility and agreement with findings from anorectal manometry and electromyography. Clin. Gastroenterol. Hepatol. 12, 2049–2054. Garg, H., Singh, S., Bal, K., 2011. Approach to the diagnosis of anorectal disorders. JIMSA 24, 89–90.
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New Concepts in the Management of Septic Perianal Conditions
Gopal, D.V., 2002. Diseases of the rectum and anus: a clinical approach to common disorders. Clin. Cornerstone 4, 34–48. Gould, S.W., Martin, S., Agarwal, T., Patel, B., Gedroyc, W., Darzi, A., 2002. Image-guided surgery for anal fistula in a 0.5T interventional MRI unit. J. Magn. Reson. Imaging 16, 267–276. Guillaumin, E., Jeffrey, R.B., Shea, W.J., Asling, C.W., Goldberg, H.I., 1986. Perirectal inflammatory disease: CT findings. Radiology 161, 153–157. Halligan, S., Stoker, J., 2006. Imaging of fistula in ano. Radiology 239, 18–33. Holzheimer, R.G., Mannick, J.A. (Eds.), 2001. Surgical Treatment: Evidence-Based and Problem-Oriented. Zuckschwerdt, Munich. Lacy, B.E., Weiser, K., 2009. Common anorectal disorders: diagnosis and treatment. Curr. Gastroenterol. Rep. 11, 413–419. Law, P.J., Bartram, C.I., 1989. Anal endosonography: technique and normal anatomy. Gastrointest. Radiol. 14, 349–353. Nelson, H., Cima, R.R., 2007. Anus. In: Sabiston Textbook of Surgery, eighteenth ed,. Saranovic, D., Barisic, G., Krivokapic, Z., Masulovic, D., Djuric-Stefanovic, A., 2007. Endoanal ultrasound evaluation of anorectal diseases and disorders: technique, indications, results and limitations. Eur. J. Radiol. 61, 480–489. Schubert, M.C., et al., 2009. What every gastroenterologist needs to know about common anorectal disorders. World J. Gastroenterol. 15, 3201–3209. Spencer, J.A., Chapple, K., Wilson, D., Ward, J., Windsor, A.C., Ambrose, N.S., 1998. Outcome after surgery for perianal fistula: predictive value of MR imaging. AJR Am. J. Roentgenol. 171, 403–406. Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 268–269, 452, (Chapters 5 and 6). Van Assche, G., Vanbeckevoort, D., Bielen, D., et al., 2003. Magnetic resonance imaging of the effects of infliximab on perianal fistulizing Crohn’s disease. Am. J. Gastroenterol. 98, 332–339. Van Outryve, M.J., Pelckmans, P.A., Michielsen, P.P., Van Maercke, Y.M., 1991. Value of transrectal ultrasonography in Crohn’s disease. Gastroenterology 101, 1171–1177. Van Outryve, M., Pelckmans, P., Fierens, H., Van Maercke, Y., 1994. Transrectal ultrasonographic examination of the anal sphincter. Acta Gastroenterol. Belg. 57, 26–27. Yousem, D.M., Fishman, E.K., Jones, B., 1988. Crohn disease: perirectal and perianal findings at CT. Radiology 167, 331–334.
FURTHER READING SWCRS (n.d.) http://www.swcrs.com.au/.
Diagnosis of Perianal Diseases Riyadh Mohammad Hasan
Contents 1 2 3 4 5 6
Introduction History Physical Examination Digital Rectal Examination Anoscopy/Proctoscopy Laboratory Investigations 6.1 Stool Examination 6.2 Histopathological Examination 7 Imaging Studies 7.1 Fistulography 7.2 Anorectal Endosonography (Endorectal Ultrasound) 7.3 Computed Tomography 7.4 MRI (Magnetic Resonance Imaging) 8 Manometry 9 Defecography 10 Electromyography References Further Reading
33 34 34 35 36 36 36 36 37 37 37 38 38 40 41 43 43 44
1 INTRODUCTION Anorectal disorders are common, and their prevalence in the general population is probably much higher than that seen in clinical practice and hospitals, as most patients do not seek medical attention because of embarrassment (Gopal, 2002). These disorders affect men and women of all ages. The symptoms of anorectal disorders are nonspecific, ranging from mildly irritating pruritus ani to potentially severe pain (Lacy and Weiser, 2009). The diagnosis of anorectal disorders consists of taking a careful history and performing a physical examination before the patient can be subjected to various forms of investigation.
New Concepts in the Management of Septic Perianal Conditions https://doi.org/10.1016/B978-0-12-816111-1.00005-7
© 2018 Elsevier Inc. All rights reserved.
33
34
New Concepts in the Management of Septic Perianal Conditions
2 HISTORY Diagnosis of anorectal disorders begins with a medical history. Pain, bleeding, discharges (either mucoid, purulent or fecal) or change in bowel habits are the common presenting symptoms. It is also important to enquire about other associated illnesses, medications, family history, bleeding tendency, and sexual contacts (Nelson and Cima, 2007). The most evident symptom of perianal abscess is severe pain in the anal region of a short duration, usually 2–3 days. Pain is severe, throbbing in character, and increased by sitting and walking. The differential diagnoses of rectal pain are anal fissure, thrombosed hemorrhoid, levator ani syndrome, proctalgia fugax, coccydynia, fecal impaction, neoplasm (whether rectal, pelvic, or cauda equine), idiopathic, inflammatory bowel diseases (ulcerative colitis, Crohn’s disease), solitary rectal ulcer, pruritis ani, trauma, anal sex, constipation, diarrhea, familial rectal pain, endometriosis, pelvic inflammatory disease, prostatitis, and foreign body (Schubert et al., 2009). Other patients may give a history of discharge, which is generally a presenting symptom of fistula-in-ano; the discharge may either be mucoid, purulent, or fecal, and it must be differentiated from that of pilonidal sinus, hidradenitis suppurativa, and infected ruptured sebaceous cyst. Fistula-in-ano is more common in males than females, and usually arises in their third, fourth, and fifth decades of life for unknown reasons. Patients usually have a recurrent leakage of blood and pus after either surgical or spontaneous drainage of an abscess, which is a feature strongly suggestive of the development of a fistula. In some patients, the recurrence of perianal abscess may indicate the presence of an underlying fistula behind. Other general symptoms like fever (or in advanced cases, rigors and sweating) may be present. Retention of urine may be the presenting complaint in perianal abscesses.
3 PHYSICAL EXAMINATION The patient is usually examined in left lateral position with buttocks projecting slightly beyond the edge of the table. The perianal area should be inspected for any indurated, hot, tender mass felt in the region, skin tags, excoriations, scars, or any change in color or appearance. It is fairly easy to diagnose an abscess just by looking at and touching it. Intersphincteric abscesses produce few or no external features, but they can be diagnosed by the intense pain they produce, which is usually described as deep inside, and is made worse by coughing and sneezing. In supralevator abscess, the
Diagnosis of Perianal Diseases
35
patient presents with fever and deep rectal pain, and there will be minimal features on external examination. Digital examination may show a tender supralevator induration above the anorectal ring. One must pay attention to the presence of fistula, which is a tract connecting two openings, one internal (which is considered the primary opening) and the other external (which is considered the secondary opening). The internal opening is often found at the dentate line, mostly at a crypt in the midline posteriorly. The treating surgeon needs to know critically important features of fistulas in order to be able to deal with them effectively. These are the primary opening, the site(s) of the secondary opening(s), the course of the fistulous track, the presence of secondary extensions, and the presence of associated diseases. The secondary opening can usually be seen as an elevated nodule of granulation tissue near the anal margin exuding pus or serosanguinous fluid. Intersphincteric fistulas usually have an external opening very close to the anal verge. Sometimes, the tract can be felt as an indurated cord, especially in simple superficial fistulas. An external opening that exudes feces or gases is mostly connected to the rectum, not to the anal canal. Defining the internal opening is the most crucial and sometimes difficult part of diagnosis and treatment. In fact, the internal opening is the crypt where the abscess originated. It may be felt during rectal examination as an indurated area. Probing was once used to define the internal opening, but probing in the awake patient is painful and may be dangerous because it may force a false tract. Many methods are used to find this opening in case it can’t be felt on rectal examination. Goodsall’s rule is a useful method of predicting the site of this opening.
4 DIGITAL RECTAL EXAMINATION This is very important examination in anorectal diseases and should not be missed. The index finger is lubricated with xylocaine jelly for digital examination, which helps in appreciating any mass, induration, stricture, apart from assessing the resting tone and strength of squeeze pressure. A gloved, lubricated finger is placed at the anal verge and gently inserted through the anal canal into the rectum. Rectal mucosa is systemically examined for benign or malignant lesions. It is possible to feel at least 10 cm from anal verge. Assessment of the anal sphincter is also made with assessment of resting tone and voluntary contraction. In males, the prostate can be assessed whereas in females, the rectocele can be detected after pushing the vaginal wall forward. (Nelson and Cima, 2007). Digital examination is probably the
36
New Concepts in the Management of Septic Perianal Conditions
best way of identifying the swelling, but pain may make this examination too difficult or even impossible. Sometimes, the patient may need examination under anesthesia to get an accurate diagnosis.
5 ANOSCOPY/PROCTOSCOPY A visual examination of the lower part of rectum and anal canal through a proctoscope must be done. Anoscopy and proctosigmoidoscopy can detect any growth in the anal canal. Anoscopy enables a satisfactory examination of anal canal and distal rectum. Endoscopy in the form of sigmoidoscopy or proctoscopy is used for detecting the primary opining of the fistula but usually an anoscope can suffice, which may show the primary opening as an enlarged papilla. For complete examination of the anorectum, proctosigmoidoscopy is the preferred method. Any suspicious area can be biopsied. The proctoscope with obturator in situ is well lubricated and introduced into the anal canal; while introducing the device, one must remember that the anal canal is directed upwards and forwards towards the umbilicus of the patient. After it has been fully introduced, the obturator is taken out, and the inside of the proctoscope is well illuminated. Hemorrhoids, internal opening of the fistulous tract, anal polyps, fissures, and ulcerations can be identified (Garg et al., 2011). If doubt still exists about the location of the primary opening, a trial of injection of hydrogen peroxide with or without methylene blue and visualization of bubbles at the internal opening either directly or through endoscopy or transrectal ultrasonography. This method is also useful in the operating theater to define the internal opening prior to probing the fistula. A sigmoidoscope has the additional benefit of ruling out the presence of inflammatory bowel disease, diverticulitis with perforation and fistulization, and more seriously, low rectal and anal canal carcinoma presenting with fistula.
6 LABORATORY INVESTIGATIONS 6.1 Stool Examination Stool Examination if infectious diarrhea or sexually transmitted disease is suspected.
6.2 Histopathological Examination Histopathological Examination is done to know the histological diagnosis of the mass or the suspicious area seen in proctosigmoidoscopy.
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7 IMAGING STUDIES Some rare deep abscesses might require ultrasound, CT scan, or even MRI for an accurate diagnosis. Imaging studies which can help determine the diagnosis in cases of a deep nonpalpable perirectal abscess include pelvic CT scan, MRI or trans-rectal ultrasound. These studies are not necessary for cases in which the diagnosis can be made upon physical examination (Beets-Tan et al., 2001).
7.1 Fistulography Fistulography is a good diagnostic method for detecting the internal opening in a fistula-in-ano, and it is still used in spite of the introduction of newer, more informative methods. This simple and affordable procedure can be done in an outpatient clinic, but it has two weak points: the inability to define secondary extensions due to insufficient filling with contrast, and the nonvisualization of anal sphincters, which is the most important factor determining the outcome of continence (Halligan and Stoker, 2006).
7.2 Anorectal Endosonography (Endorectal Ultrasound) This was the first method to show the details of anal wall anatomy, especially the sphincters (Law and Bartram, 1989). It can be used with or without injection of hydrogen peroxide, but it has an unfortunately limited field of view, making it excellent imaging procedure for the diagnosis of intersphincteric fistulas and their relationship to the anal sphincters, but less so for primary superficial, suprasphincteric, and extrasphincteric tracks or secondary extensions (Van Outryve et al., 1991, 1994). These limitations may be overcome by the improved US transducers with three-dimensional (3D) equipment (Saranovic et al., 2007). Currently, transrectal ultrasound is reserved for complicated cases, especially recurrent fistulas and supralevator fistulas where it is important to show the fistula’s relationship to the sphincters, and there is hope that it may be more widely used in the future. Transrectal ultrasounds are an accurate means of delineating anatomy in relation to a fistula. It is easily performed and less expensive than Magnetic Resonance Imaging (MRI), but it is not appropriate for the patient with severe anal pain or an anatomical stricture. The exact choice of which modality to use depends on local expertise, cost, and the equipment available.
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New Concepts in the Management of Septic Perianal Conditions
7.3 Computed Tomography Computed tomography (CT) is a useful technique for extrasphincteric fistulas, but it has limitations. It is used with rectal and intravenous contrast material, but it has poor resolution for soft tissue, which makes it unable to analyze anal fistulous tracks (Guillaumin et al., 1986; Yousem et al., 1988). The overall sensitivity of computed tomography in identifying abscess is 77%, and it lacks sensitivity in detecting perirectal abscess, particularly in the immunocompromised patient (Caliste et al., 2011). 7.3.1 Virtual Colonoscopy This procedure is done using helical CT; contrast agents may be used orally or rectally with insufflations. The accuracy of this technique may approach that of colonoscopy.
7.4 MRI (Magnetic Resonance Imaging) Adopting endoanal coils and phased array imaging has contributed to the evolution of using MRI to evaluate anorectal disease (Buchanan et al., 2004; (Berman et al., 2007) (Fig. 1). Magnetic resonance imaging is now considered the “gold standard” for fistula imaging, but it is limited by its availability and cost and is usually reserved for difficult, recurrent cases. It is used in the detection of secondary extensions, which are one of the main causes of surgical failure. In addition, it has the ability to study the integrity of the sphincter complex and to define the relationship of the fistulous track to the anal sphincters before performing fistulotomy to be sure of preserving continence. (Spencer et al., 1998; Chapple et al., 2000). In cases of recurrence and severe inflammation, the clinical examination will have difficulty delineating the position of the abscess and/or fistulous tract making planning surgical intervention very difficult and the risk of surgical failure higher. Here, MRI may indicate the site of abscess in cases in which localization is difficult, that is, intersphincteric and supralevator abscesses (Fig. 2). MRI may show the extension of an existing abscess through both ischioanal fossae to form a horseshoe abscess (Fig. 3). MRI is also useful for showing the external and internal openings and the track, and it is especially useful in recurrent fistula and cases in which there are secondary extensions (Figs. 4 and 5). MRI is useful in monitoring therapy, especially in complicated fistulas and in Crohn’s disease fistulas, and when using fibrin glue, because sometimes the external opening is closed, but the track is still not healed.
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Spermatic cords
Sartorius m. Right femoral n. Rectus femoris m. Right superficial femoral a. Right deep femoral a. Iliopsoas m. Right superficial femoral v.
Left superficial femoral a. Left femoral n. Left deep femoral a. Left superficial femoral v. Pectineus m. Pubic symphysis Prostate Prostatic urethra
Obturator externus m. Quadratus femoris m. Ischial tuberosity Sciatic n. Ischioanal fossa
Anus Internal pudendal vessels Sciatic n. Levator ani m.
Gluteus maximus m. Anococcygeal ligament
(A)
Subcutaneous fat
Spermatic cords
Sartorius m. Right femoral n. Rectus femoris m. Right superficial femoral a. Right deep femoral a. Iliopsoas m. Right superficial femoral v.
Obturator externus m. Ischioanal fossa Quadratus femoris m. Ischial tuberosity Sciatic n.
Left superficial femoral a. Left femoral n. Left deep femoral a. Left superficial femoral v. Pectineus m. Pubic symphysis Prostate Prostatic urethra Anus Sciatic n. Levator ani m.
Gluteus maximus m. Anococcygeal ligament
(B) Fig. 1 (A,B) The normal male anatomy of the perineum at the level of the mid anal canal in the axial plane. ES ¼ external sphincter, IA ¼ ischioanal fossa, InS ¼ intersphincteric space, IS ¼ internal sphincter. (From Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 268–269 (Chapter 6).)
MRI is excellent for showing the extent of healing and the effect of infliximab or fibrin glue in the process of healing (Buchanan et al., 2003; Van Assche et al., 2003). MRI may also guide surgical treatment, not only preoperatively but also intraoperatively to identify the extensions of the fistula, preventing incomplete procedures and the possibility of recurrence, especially in complex and recurrent fistulas (Gould et al., 2002). Buchanan et al. recently studied a cohort of 108 patients with recurrent fistulas using digital examination, endoanal ultrasound, and MRI on each patient. Digital
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New Concepts in the Management of Septic Perianal Conditions
Thecal sac
Erector spinae mm.
Ilium Sacrum Gluteus maximus m. Sigmoid colon Rectosigmoid colon
Rectum Ischiorectal fossa Anus
Ischioanal fossa
Levator ani m.
(A)
Ilium
Thecal sac Sacrum
Sigmoid colon Rectosigmoid colon Rectum Ischiorectal fossa Anus
Ischioanal fossa
(B) Fig. 2 (A,B) High signal intensity fluid collection along the right posterolateral aspect of the anal canal with Simple intersphincteric fistula. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 474–475 (Chapter 5).)
examination correctly identified 61% of tracks, compared with 81% of tracks found by endoanal ultrasound, and 90% by MRI (Buchanan et al., 2004).
8 MANOMETRY Surgeons may request anal manometry to further investigate problems of incontinence in defecation. Manometry tests the strength of sphincter muscle. Some authors advocate preoperative manometry in order to choose the
Diagnosis of Perianal Diseases
Sartorius m. Rectus femoris m. Pectineus m. Iliopsoas m.
Mons pubis Clitoris Left greater saphenous v. Left superficial femoral a. Left deep femoral a. Left superficial femoral v. Left deep femoral v. Pubic symphysis
Obturator externus m.
Urethra
Obturator internus m. Internal pudendal vessels
Vagina
Ischium Ischioanal fossa Gluteus maximus m. Levator ani m.
Sartorius m. Rectus femoris m. Pectineus m. Iliopsoas m. Obturator externus m. Obturator internus m. Internal pudendal vessels Ischium Ischioanal fossa Gluteus maximus m.
41
Internal pudendal vessels Anus Ischioanal fossa Horseshoe abscess Anococcygeal ligament
Mons pubis Clitoris Left greater saphenous v. Left superficial femoral a. Left deep femoral a. Left superficial femoral v. Left deep femoral v. Pubic symphysis Urethra Vagina Internal pudendal vessels Anus Ischioanal fossa Horseshoe abscess
Fig. 3 Horseshoe abscess. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 452 (Chapter 5).)
correct therapeutic management according to the risk of incontinence (Grade B) (Holzheimer and Mannick, 2001).
9 DEFECOGRAPHY Barium defecography is performed by injecting barium contrast mixed with Metamucil or another thickening agent into the rectum and taking lateral images of the anorectum during pelvic floor contraction, before, during, and after attempted defecation (Agachan et al., 1996). The angle between the axis of the rectum and the anal canal provides an indirect measure of whether the puborectalis muscle relaxes, which is the normal response, or contracts, indicative of defecatory disorder, during simulated defecation. Extra information is obtained on structural causes of outlet dysfunction
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New Concepts in the Management of Septic Perianal Conditions
Cervix Small bowel Cardinal (transverse cervical or Mackenrodt’s) ligament Lateral vaginal fornix Rectum Ischiorectal fossa Ischioanal fossa Anus
Outer cervical stroma Inner cervical stroma Cardinal (transverse cervical or Mackenrodt’s) ligament Left ovary Endocervical glands Endocervical canal Lateral vaginal fornix Transsphincteric fistula
Fig. 4 Transsphincteric fistula is distinguished by location of the internal opening in the middle third of the anal canal. (Edited from Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 473 (Chapter 5).)
Fig. 5 Coronal MRI STRI image reveals a right sided extrasphincteric fistula (straight arrows) with its enteric communication in the rectum (curved arrow). (From Chapman, A.H., Guthrie, J.A., Robinson, J.A., 2003. The stomach and duodenum. In: Sutton, D. (Ed.), Text Book of Radiology and Imaging, vol. 1, seventh edition. Churchill Livingstone, pp. 654 (Chapter 19).)
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including rectal prolapse, rectocele, and enterocele. Defecography was once regarded as the gold standard for diagnosis of defecatory disorder. Consequently, defecography can identify impaired evacuation in patients with symptoms of defecatory disorder, but with normal electromyography testing (Chiarioni et al., 2014).
10 ELECTROMYOGRAPHY Electromyography (EMG) may help in the assessment of anorectal incontinence, constipation, or any other pelvic floor disorder (Nelson and Cima, 2007). Anorectal disease is common and its incidence is increasing over the last few decades among populations. Diseases of the ano-rectum are usually easy to diagnose via patient’s history, which provides a great deal of information, and clinical examination with digital examination supplemented with anoscopy or proctoscopy help in diagnosis. Specialized investigations are needed in selected group of patients (Garg et al., 2011).
REFERENCES Agachan, F., Pfeifer, J., Wexner, S.D., 1996. Defecography and proctography. Results of 744 patients. Dis. Colon Rectum 39, 899–905. Beets-Tan, R.G., Beets, G.L., van der Hoop, A.G., Kessels, A.G., Vliegen, R.F., Baeten, C.G., van Engelshoven, J.M., 2001. Preoperative MR imaging of anal fistulas: does it really help the surgeon? Radiology 218, 75–84. Berman, L., Israel, G.M., McCarthy, S.M., Weinreb, J.C., Longo, W.E., 2007. Utility of magnetic resonance imaging in anorectal disease. World J. Gastroenterol. 13, 3153–3158. Buchanan, G.N., Bartram, C.I., Phillips, R.K., et al., 2003. Efficacy of fibrin sealant in the management of complex anal fistula: a prospective trial. Dis. Colon Rectum 46, 1167–1174. Buchanan, G.N., Halligan, S., Bartram, C.I., Williams, A.B., Tarroni, D., Cohen, C.R., 2004. Clinical examination, endosonography, and MR imaging in preoperative assessment of fistula in ano: comparison with outcome-based reference standard. Radiology 233, 674–681. Caliste, X., Nazir, S., Goode, T., et al., 2011. Sensitivity of computed tomography in detection of perirectal abscess. Am. Surg. 77, 166–168. Chapple, K.S., Spencer, J.A., Windsor, A.C., Wilson, D., Ward, J., Ambrose, N.S., 2000. Prognostic value of magnetic resonance imaging in the management of fistula-in-ano. Dis. Colon Rectum 43, 511–516. Chiarioni, G., Kim, S.M., Vantini, I., et al., 2014. Validation of the balloon evacuation test: reproducibility and agreement with findings from anorectal manometry and electromyography. Clin. Gastroenterol. Hepatol. 12, 2049–2054. Garg, H., Singh, S., Bal, K., 2011. Approach to the diagnosis of anorectal disorders. JIMSA 24, 89–90.
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Gopal, D.V., 2002. Diseases of the rectum and anus: a clinical approach to common disorders. Clin. Cornerstone 4, 34–48. Gould, S.W., Martin, S., Agarwal, T., Patel, B., Gedroyc, W., Darzi, A., 2002. Image-guided surgery for anal fistula in a 0.5T interventional MRI unit. J. Magn. Reson. Imaging 16, 267–276. Guillaumin, E., Jeffrey, R.B., Shea, W.J., Asling, C.W., Goldberg, H.I., 1986. Perirectal inflammatory disease: CT findings. Radiology 161, 153–157. Halligan, S., Stoker, J., 2006. Imaging of fistula in ano. Radiology 239, 18–33. Holzheimer, R.G., Mannick, J.A. (Eds.), 2001. Surgical Treatment: Evidence-Based and Problem-Oriented. Zuckschwerdt, Munich. Lacy, B.E., Weiser, K., 2009. Common anorectal disorders: diagnosis and treatment. Curr. Gastroenterol. Rep. 11, 413–419. Law, P.J., Bartram, C.I., 1989. Anal endosonography: technique and normal anatomy. Gastrointest. Radiol. 14, 349–353. Nelson, H., Cima, R.R., 2007. Anus. In: Sabiston Textbook of Surgery, eighteenth ed,. Saranovic, D., Barisic, G., Krivokapic, Z., Masulovic, D., Djuric-Stefanovic, A., 2007. Endoanal ultrasound evaluation of anorectal diseases and disorders: technique, indications, results and limitations. Eur. J. Radiol. 61, 480–489. Schubert, M.C., et al., 2009. What every gastroenterologist needs to know about common anorectal disorders. World J. Gastroenterol. 15, 3201–3209. Spencer, J.A., Chapple, K., Wilson, D., Ward, J., Windsor, A.C., Ambrose, N.S., 1998. Outcome after surgery for perianal fistula: predictive value of MR imaging. AJR Am. J. Roentgenol. 171, 403–406. Torigian, D.A., Hammell, M.T.K., 2013. Netter’s Correlative Imaging: Abdominal and Pelvic Anatomy. Elsevier-Saunders, pp. 268–269, 452, (Chapters 5 and 6). Van Assche, G., Vanbeckevoort, D., Bielen, D., et al., 2003. Magnetic resonance imaging of the effects of infliximab on perianal fistulizing Crohn’s disease. Am. J. Gastroenterol. 98, 332–339. Van Outryve, M.J., Pelckmans, P.A., Michielsen, P.P., Van Maercke, Y.M., 1991. Value of transrectal ultrasonography in Crohn’s disease. Gastroenterology 101, 1171–1177. Van Outryve, M., Pelckmans, P., Fierens, H., Van Maercke, Y., 1994. Transrectal ultrasonographic examination of the anal sphincter. Acta Gastroenterol. Belg. 57, 26–27. Yousem, D.M., Fishman, E.K., Jones, B., 1988. Crohn disease: perirectal and perianal findings at CT. Radiology 167, 331–334.
FURTHER READING SWCRS (n.d.) http://www.swcrs.com.au/.